The upper lateral incisor root, also known as the maxillary lateral incisor root, is typically single-rooted, with a slightly curved and tapered shape, generally curving distally towards the apex, and is considered to be the longest root in relation to its crown size compared to other maxillary incisors; it usually has a single root canal running through its center, with the mesial side of the root often appearing slightly flatter than the distal side.